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L.. GgoRoWELL. TYMPAN MEGHANISM FOR PBINTING MAOHINES. No. 596,025. Patented Dec.21.1897.

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L. G'..GR0WELL. TYMPAN MECHANISM' FOR PRINTING MAC'HINBS.

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(No'ModeL) 5 Sheets. Sheet 5.

L. O. GROWELL. TYMPAN MEGHANISM FORPRINTING MACHINES.

[ai/enim* UNITED' STATES PATENT OFFICE.

LUTHER O. OROWELL, OF BROOKLYN, NEW YORK, ASSIGNOR TO ROBERT HOE, THEODORE H. `MEAD, AND OHARLES W. OARPENTER, OF NEW YORK, N. Y.

TYMPAN MECHANISM FOR PRINTING-MACHINES.

SPEGIFICATION forming part of Letters Patent No. 596,025, dated December 21, 1897. 4 Application filed March 7, 1895. Serial No. 540,826. (No model.)

To all whom, it may concern:

Be it known that I, LUTHER O. OROWELL, a citizen of the United States, residing in the city of Brooklyn, county of Kings, and State of New York, have invented certain new and useful Improvements in Tympan Mechanisms for Printing-Machines, fully described and represented in the following specification and the accompanying drawings, forming a part [o of the same.

This invention relates to that class of printing-machines in which the impression-cylinder is provided with a tympan or Offset-surface in the form of a long sheet orj web (here- 1 5 inafter called the tympan capable of being wound from one roller to another and with means for shifting the'same while the cylinder carrying it is moving, whereby when an impression or impressions have been made on the exposed portion of the tympan and the set-off on the tympan makes it desirable to present a fresh surface thereof for printing contact the tympan is moved so as to transfer a fresh portion of it over that surface of the impression which is opposedvduring the printing Operation to the type or printing-surface of the form-carrying bed or printing-cylinder, thus preventing the blurring of printed sheets when they are being perfected. f The invention consists in a spring-actuate mechanism whereby the wind-up roller is rotated to shift the tympan mechanism whereby the shifting vmovement of the tympan is controlled, mechanism whereby the extent to which the tympan is shifted is governed, a tripping mechanism whereby the time of the shifting Operation is determined, and various constructions and combinations of mechanisms, all of which are he'reinafter fully explained, and pointed out in the claims.

In the drawings, which illustrate a practical embodiment of this inveution, Figure 1 represents by a side elevation, or as seen in 45 the direction of the arrow 1 in Figs. 2 and 3, the impression-cylinder of a printing-machine provided With a shifting tympan, the central portion of the cylinder being broken away or omitted to permit a larger scale of illustra- 5o tion. Fig. 2 is an end elevation ofsaid cylinder, taken on the section-line 2 of Fig. 1, as seen looking in the direction of the arrow 2 of Fig. 1, the Operating-Cam being indicated by a dotted line. Fig. 3 is a sectional elevation taken on the section-line 3 of Fig. 1, as seen looking in the direction of the arrow 3 of Fig. 1. Fig. 4 is an end elevation similar to Fig. 2, illustrating the same mechanisms, but presenting them indifferent positions; and Fig. 5 is an opposite end elevation.

The drawings illustrate an impression-cylinder of a printing-machine provided with a -tympan and appliances for supporting and shifting the same, as well as so much of the framework as is necessary to instruct any one skilled in the printing art in practically carrying this invention into effect. An impression-cylinder thus equipped with a shifting tympan may operate in connection with a flat form-carrying bed or in connection With a 7o rotating form-carrying cylinder, and will' of course in either case be that impression-cylinder used in making the second impression. For controlling sheets while the same are being printed it is supplied with grippers 50, as is common, by which each sheet is held upon that portion of the periphery of the Cylindershell constituting its impression surface, which in the illustrated example extends from the gripper-operating point to an opposite point, while the rest of the cylinder-shell is omitted to enable ready access to be had to the tympan-rollers and interior mechanisms. The tympan 51, in the form of a long web rolled up tightly on a delivering-roller, as 90, is led therefrom, passes over `said impression-surface, and is carried onto and secured to a winding-up roller 91. The deliveringroller may be mounted in bushings, as 60 61, by its spindle 10, and the roller 91 may be 90 mounted in bushings, as 70 71, by its spindle 11. The bushings 60 61 71 are removable, and the bushing 70, which acts as a journal, is secured to -the spindle 11 by a setscrew,

which arrangement provides for detaching 9 5 and exchangingthe rollers 90 91. The delivering-roller 90, from which the tympansheet is unwound, is arranged to turn freely in its bearings; but the unwinding action or shifting movement of the tympan wound upon mo it is controlled by a roller 12, which acts as a brake-roller to hold the tympan stationary when it is in use as an Offset-surface, and, when the tympan is shifting, not only as a frietional tension device aiding its regular movement, but, in consequence of its constant contact with the surface of the rolled tympansheet, as a measuring-roller through which is governed'the length of web or extent of tympan which is unwound under its control. This controlling-roller12 is hung to turn freely in arms 22 23, fast ou a rock-shaft 24, that is jourualed in the cylinder-heads and moved to press the roller 12 into contact with the periphery of `the roll of tympan-web wound upon the delivering-roller 90 by means of a rock-arm 40, that is constantly pressed by means of the spring-actuated rod 26 to hold this controlling-roller to duty. The bushing Ior journal of the winding-up or receiving rollei` 91 carries fast upon it outside of the cylinder-head a pinion 13, meshing with a wheel 14, that turns loosely upon a shaft 2, which is journaled in the cylinder-heads, to one face of which wheel 14 is secured a ratchetwheel 21, Whose detent-pawl 20 is pivoted to the cylinder-head. This winding-up or receiving roller 91 is thus geared with the shaft 2, that has Secured to it a volute drivingspring 36, which has its inner part fastened to the shaft 2 and its outer part fastened to a stud 3, projecting from the c'ylinder-head. This spring 36 may thus, either primarily or as an auxiliary, drive or revolve the winding-up roller 91 for shifting the tympan 51. This Spring-carrying shaft 2 is independently revolved to coil said spring by means of a pinion 17, fast on its outer end, which pinion is engaged by a segment 18, that swings on a pivot 28, journaled in the cylinder-head. This shaft 2 also carries fast upon it an'd near the inner face of pinion 17 a ratchet-wheel 5, the teeth of which are engaged by a pawl 6, that is pivoted to the outer face of the wheel 14. The segment 18 is cut away to clear the main shaft of the impression-cylinder and is driven in the direction its arrow 19 points in Eig. 4 to rotate the shaft 2, and thus coil or wind up the Spring 36 by means of a cam 30, fast to the framework, with which engages a stud and roller 29, that projects outwardly from the segment. This cam 30 thus operates to forcibly move the segment in the direction indicated and through the pinion 17 revolves the shaft 2, the attained position of which is secured by the pawl 6, which movement will, as is apparen t, compress the Spring upon the rod 27 and thus capacitate said Spring to rotate the shaft 2 in a contrary direction to rotate the winding-up roller when it may so act. XVhen, however, the shaft 2 is released, so as to be moved by its actuating-Spring 36, as will hereinafter be explained, it will be revolved in a contrary direction, rotating the pinion 17, and with it the ratchetwheel 5, attached thereto, when the pawl 6, being engagcd with a tooth of the ratchetwheel, is driven thereby, and in turn drives the wheel 14, to which said pawl is attached, and said wheel 14 rotates the pinion 13 to revolve the Wind-up roller 91, the pawl 20 then dragging over the ratchet-wheel 21, carried by the wheel 14, to secure its attained position when its rotation ceases. During this movement the segment 19 follows the pinion 17, being actuated by the stored power of its Spring-rod 27.

The mechanism for governing the extent of each shifting movement of the tympan consists of the governing-disk 31 and its associated devices, now to be described. There is a pinion 15 fast on the outer end of the shaft of the controlling or brake-roller 12, which pinion is engaged by a loose gear-wheel 16 on the outer end of the shaft 24, to which the carrying rock-arms 22 23 of said roller 12 are fixed, said wheel 16 being made fast to the governing-disk 31. This disk has a socket 8, that is engaged by a tooth 9, projecting laterally from a lever 32, pivoted at 33 and normally pressed by a Spring-rod 34, so as to hold the tooth 9 in the socket 8 of the governing-disk 31, and thus lock the governing mechanism to hold the tympan stationary. In order to determine the time when this propelling movement of the spring-actuated shaft 2 shall rotate the wind-up roller 91 and shift the tympan, this mechanism is pro- Vided fol` looking the controlling-roller 12 stationary, so that it will act as a brake-roller and suspend any movement of the unwindroller 90, and a tripping-bolt 35 is provided for Operating this looking mechanism, so that the unwind-roller may at predetermined times be rotated by the spring actuating or driving mechanism. The tripping-bolt 35 coacts with the lever 32, the outer end of which is curved, so that it will be moved easily when b'rought into contact with said tripping-bolt 35, whereby it is swung inwardly to raise its tooth 9 out of the socket Sand release the governing mechanism. This tripping-bolt 35 is mounted in the framework of the machine in which the bearings for the shaft of the impression-cylinder are supported, and it may be moved inward or toward the cylinder-head to ntercept the lever 32 and withdrawn out of its pathway by clockwork suitably timed for the purpose or by any other common means that is independent of the printing-machine, or it may be by simple means connected with the printing-machine.

It will now be apparent that so long as the governing-disk 31 is locked by the tooth 9 of the lever 32-that is, so long as the bolt 35 is withdrawn or held out of the pathway of the lever 32-the controlling-roller 12 will act as a brake by reason of the pressure exerted by its Spring-rod 26, and thus hold the unwindroller 90 against any paying-off movement of the tympan, and that the latter Will in turn prevent the windingup movement of the roller 91, and hence resist any rotative movement of the pinion 13, wheel 14, pawl 6,

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' by the controlling mechanism.

ratchet-wheel 5, pinion 17, and segment 18, which otherwise would all be moved by the power exerted by the actuating-spring on rod 2 or the Spring-rod 27. It will also be observed that in this locked condition of the parts, as in Fig. 2, although the segment 18 revolves with the cylinder, its stud 29 will move past the stationary cam 30 without being actuated thereby, since it is only after said segment has been moved as a result of the tripping action of the bolt 35 that its stud 29 is brought into the range of action upon it of this cam 30. In the condition of the parts shown in Fig. 2 the tympan will be stretched taut from the unwinding-roller 90 smoothly over the mpression-surface of the impression-cylinder and onto the winding-up roller 91, being securely held by the controlling roller 12, then Operating as a brake, and the spring on the shaft 2 will have been compressed and thus be capable of rotating the winding-up roller when permitted to so act If now that portion of the tympan which is stretched over the impression-surface of the cylinder has become so soiled as to need to be shifted or the time for the Operation of the tripping mechanism has arrived, an inward movement of the tripping-bolt 35 will project it into the pathway of the lever 32, and when the same contacts therewith after the impression-surface of the cylinder has passed out of contact with the form this lever will be swung to detach the tooth 9 from .the socket 8 of the governing-disk 31, wh'ereupon the governingdisk 31 and wheel 16 are free to rotate, thus allowing the winding-up roller 91 to be rotated by the action of the actuating-spring' on shaft 2, to draw upon the tympan, unwind it from the roller 90, and wind it up on the roller 91. In this movement of the tympan the controlling-roller 12 will be rotated by surface contact with the rolled web and will, through the pinion 15 and wheel 16, rotate the governing-disk 31, and as the roller 12 is held with Spring-pressure upon the' periphery of the rolled web the eXtent of its surface movement, and consequently that of the web unwound from the roller 90, will be' governed by the peripheral length of the disk 31, and thus a length of the tympan corresponding thereto will be unwound or let ofi the roller 90, and a portion of the tympan equal to that so let off or unwound will be taken up or wound upon the take-up roller 91, said rollers 90 and 91 being thus simultaneously rotated at an equal speed and to the same surface extent and finally brought to a state of rest as the tooth 9 again becomes seated in the socket 8 of the disk 31. The tympan as it is thus moved tol carry its soiled portion onward and present a clean portion on the impression-surface of the cylinderwill be transferred under suitable tension exerted by the measuring-roller 12 to cause it not only to be laid smoothly on the said impressionsurface, but be so stretched by the pull of the that one revolution ofit shall be the measure of the extent of the movement of the tympan, which may be equal to or less than the circumferential extent of the ilnpression-surface, and if it is desired that this movement shall be one-half, one-quarter, or any other proportionate distance the same may be accomplished by suitably increasing the number of the sockets 8 in the said disk or by providing disks With one socket of suitable smaller size.

It is not essential that the spring actuating the wind-up roller shall be upon the shaft 2, but the spring on the rod 27 may act as an auxiliary thereto or as a substitute therefor. With this arrangement it will be obvious that the cam 30 may move the segment 18 with sufficient force to compress the spring on rod 27, so that it will be powerful enough to act as the actuating-spring, so that when the parts are unlocked the resilient power of this spring will act to drive the wind-up roller in the same manner as the Spring on the shaft 2 is described as acting.

By the surface contact and frictional action of the controlling-roller 12 011 the rolled tympan, the size of which roll of tympan is constantly diminishing, it will be apparent that the same surface eXtent and consequent length of tympan will pass off the roller 90 at each revolution of the disk 31, no matter to what extent in size the rolled tympan may have diminished.

Thus far has been described the presence of a single tympan. It is obvious, however, that if the i'mpression-cylinder is made large enough to provide two or more impressionsurfaces as many tympans and tympan-shifting mechanisms may be provided.

The shifting mechanism may be so operated as to move the tympan a short distance at each revolution of the impression-cylinder; but this will require, as is apparent, a multiplicity of shifting movements in order to transfer an extent of tympan equal to the entire impression-surface. Further, each shifting movement may be sufficient to transfer the tympan such a distance as will carry an entire fresh surface over the impression-surface, and these shifting movements may be made after each passage of the impressionsurface, or after any number of impressions have been made, all of which will be accomplished by suitably adjusting and regulating the Operation of the shifting devices. v

What I claim is- 1. In a Printing-machine, the combination with an impression-cylinder, two tympan-carrying rollers mounted to revolve therein and IOO IIO

from which the tympan is intermedately Stretched over the impreSsion-surface of said cy1inder,a spring-actuated mechanism whereby one roller is rotated to Wind up and thus Shift said tympan, and, automatic means whereby the travel or shifting movement of said tympan is oontrolled, substantially as described.

2. In a printing-machine, the combination with an impression-cylindeI-,two tympan-carrying rollers mounted to revolve therein and from which the tympan is intermediately stretched over the impresSion-Surface of said cy1inder,a Spring-actuated mechanism whereby one roller is rotated to wind up and thus Shift said tympan, automatic means whereby the travel or shifting movement of said tympan is controlled, and, a tripping mechanism by which the time of said shifting movement is determined, substantially as described.

3. In a printing mechanism, the combination with an impressioucylinder,two tympancarrying rollers mounted to revolve therein and from which the tympan is intermediately stretched over the impression-surface of said cylinder, of a mechanism for rotating one of said rollers to wind up and thus Shift said tympan, and a mechanism whereby the extent of tympan Shifted is governed, Substantally as described.

4. In a printing mechanism, the combination with an impresSion-cylinder,t\vo tympancarrying rollers mounted to revolve therein and from which the tympan is intermediately stretched over the impreSsion-surface of said cylinder, of a mechanism for rotating one of said rollers to wind up and thus Shift said tympan, a controlling-roller running in surface contact with the unwindin g roll of tympan upon the other roller and a governing mechanism limiting the rotation of the controlling-roller, whereby the extent of tympan unwound is measured and governed, substantially as described.

In'a printing mechanism, the combination with an impreSsion-cylinder, two tympancarrying rollers mounted to revolve therein and from which the tympan is intermediately stretched over the impression-surface of said cylinder, of a mechanism for rotating one of said rollers to wind up and thus Shift said tympan, a controlling-roller running in surface contact with the unwinding roll of tympan upon the other roller, a governing mechanism limitin g the rotation of the controllingroller, and, a trippin g mechanism controllin g the time of the operationiof the mechanisms, Substantially as described.

(5. In a printing mechanism, the combination with an impresson-cylinder, and two tympan-carrying rollers mounted to revolve therein and from which the tympan is intermediately stretched over the impresSion-surface of said cylinder, of a mechanism Springactuated in one direction to rotate one of said rollers and thus wind up and Shift said tympan, and means for movin g said mechanism in the opposite direction to restore the resilient power of the Spring, substantially as described.

7. In a printing mechanism, the combination with an impreSsion-cylinder and two tyrnpan-carrying rollers mounted to revolve therein and from which the tympan is intermediately stret-ched over the impression-surface of said cylinder, of a mechanism Springactuated in one direction to rotate one of said rollers and thus wind up and Shift said tympan, means for moving said mechanism in the opposite direction to restore the resilient power of the Spring, a controlling-roller running in surface contact with the rolled-up tympan on the other roller, and, a governing mechanism limiting the rotation of the controlling-roller and consequent extent of Shifting movement of the tympan, Substantially as described.

8. In a printing mechanism, the combination with an impression-cylinder and two tympan-carrying rollers mounted to revolve therein and from which the tympan is intermediately stretched over the impreSSion-surface of said cylinder, of a mechanism Springactuated in one direction to rotate one of said rollers and thus wind up and Shift said tympan, means for moving said mechanism in the opposite direction to restore the resilient power of the Spring, a controlling-roller running in surface contact with the rolled-up tympan on the other roller, a governin g mechanism limiting the rotation of the controllingroller and consequent extent of shiftin g movement of the tympan,and a trippin g mechanism controlling the time of the Operation of the mechanisms, substantially as described.

9. The combination with the impressioncylinder and its two tympan-carrying rollers, of an actuating-spring and intermediate gearing transmitting its power to the wind-up roller to rotate the same, substantially as described. i

10. The combination with the impressioncylinder and its two tympan-carrying rollers, of an actuating-spring, intermediate gearing transmitting its power to the wind-up roller to rotate the same, and, means for reversing said gearing to restore the power of the Spring, substantially as described.

11. The combination with the impressioncylinder and its two tympan-carrying rollers, of an actuating-spring and intermcdiate rotating gearing transmitting its power to the wind-up roller to rotate the same, a Segment engaging said gearing, a Spring Operating to Swing the segment in the corresponding direction, and, means Operating to Swing said segment in the opposite direction to restore power to the springs, substantially as described.

12. The combination with the impressioncylinder and its two tympan-carrying rollers, of an actuating-spring, intermediate gearing transmitting its power to the wind-up roller to rotate the same, means for reversing said gearing to restore the power of the Spring,

IOO

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a spring-pressed controlling-roller bearing upon the surface of the tympan wound upon the paying-out roller, gearing connecting the controlling-roller with a governing-disk, and

a locking-lever controlling the rotation of said trolling-roller bearing upon the surface of the tympan wound upon the paying-out roller, gearing connecting the con trolling-roller with a governing-disk, and a locking-lever controlling the rotation of said disk, substantiallyv as described.

14. The combination with the impressioncylinder and its two tympan-carrying rollers, of an actuating-spring, intermediate gearing transmitting its power to the Wind-up roller to rotate the same, means for reversing said gearing to restore the power of the spring, a spring-pressed controlling-roller bearing upon the surface of the tympan wound upon the delivering-roller, gearing connecting the controlling-roller with a governing-disk, a locking-lever controlling the rotation of said disk, and a tripping mechanism to periodically operate said lever to release the disk and set the mechanism into Operation, substantially as described.

15. The combination with the impression= cylinder and its two tympan-carryin g rollers, of an actuating-spring and intermediate rotating gearing transmitting its power to the wind-up roller to rotate the same, a segment engaging said gearing, a spring Operating to swing the segment in the corresponding direction, means Operating to swing said segment in the opposite direction to restore power to the springs, a spring-pressed controlling-roller bearing upon the surface of the tympan wound upon the paying-ont roller, gearing connecting the controlling-roller with a governing-disk, alocking-lever controlling the rotation of said disk, and a tripping mechanism to periodically operate said lever to release the disk and set the mechanism into operation, substantially as described.

16. The combination with the impressioncylinder and its tympan-rollers 90, 91, of the pinion 13, wheel14, ratchet-wheel 21, pawl 20, ratchet-wheel 5, pawl 6, pinion 17, segment 18, a Spring-rod 27, and means for Operating said segment substantially as described.

17. The combination with the impressioncylinder and its tympan-rollers 90, 91, of the spring 36, pinion 13, wheel 14, ratchet-wheel 21, pawl 20, ratchet-wheel 5, pawl 6, pinion 17 segment 18, a sprin g-rod 27, and means for Operating said segment substantially as described.

18. The combination with the impressioncylinder and its tympan-rollers 90, 91, of the pinion 13, whee114, ratchet-wheel 21, paw120, ratchet-wheel 5, pawl 6, pinion'l', segment 18, an actuating-spring, and cam 30, substantially as described.

19. The combination with the impressioncylinder and its tympan-rollers 90, 91, of the pinion 13, Wheel 14, ratchet--wheel 21, pawl 20, ratchet-wheel 5, pawl 6, pinion 17, segment 18,an actuating-spring,cam 30,spring-pressed roller 12, its pinion 15,wheel16, socketed disk 31, and spring-seated lever 32, and means for tripping said lever substantially as described.

20. The combination with the impressioncylinder and its tympan-rollers 90, 91, of the pinion 13, wheel 14, ratchet-wheel 21, pawl 20, ratchet-wheel 5, pawl 6, pinion 17, segment 18, an actuating-spring, cam 30, springpressed roller 12, its pinion 15, wheel 16, socketed disk 31, spring-seated lever 32 and tripping-bolt 35, snbstantially as described.

21. The combination with an impressioncylinder and two tympan-carrying rollers journaled within the same for stretching a tympan from one to the other and intermediately over the impression-surface of said cylinder, and means for driving one of said carrying-rollers for winding the tympan thereon, of a controlling-roller acting by surface contact with the tympan to control its shifting movement, substantially as described.

22. The combination with an impressioncyli'nder and two tympan-carrying rollers journaled within the same for stretching a tympan from one to the other and intermediately over the impression-surface of said cylinder, and means for driving one of said carrying-rollers for winding the tympan thereon, of a controlling-roller acting by surface contact with the tympan to control its shifting movement and means governing the extent thereof, substantially as described.

23. The combination With an impressioncylinder and two tympan-carrying rollers journaled within the same for stretching a tympan from one to the other and intermediately over the impression-surface of said cylinder, and means for driving one of said carrying-rollers for winding the tympan thereon, of a controlling-roller acting by surface contact with the tympan to control its shifting movement, means governing the extent of such movement, and means determining the time thereof, substantially as described.

24. The combination With an impressioncylinder and two tympan-carrying rollers journaled within the same for stretching a tympan from one to the other and intermediately over the impression-surface of said cylinder, of a controlling-roller acting by sur- IIO lIzo

face contact with the tympan to control -the shifting movement, a spring-actuated driving-shaft for the receiving-rolier, means acting upon the delivering-roller and Operating through the tympan to control the unwinding action of the Spring, substantially as described.

25. The combination with an impressioncylinder and delivering and receiving rollers journaied Within the same for stretching a tympan from one to the other and intermediately over the impression-surface of said cylinder, and means for cansing the shifting movement of the tympan, of a controllingroller acting by surface contact with the tympan to control its shifting movement, and a governing-disk limiting the rotative movement of said roller and consequent extent of tympan shifted, substantially as described.

26. The combination With an impressioncylinder and delivering and receiving` roilers jonrnaled Within the same for stretching a tympan from one to the other and intermediately over the ii'npression-snrface of said cylinder, and means for causing the shifting movement of the tympan, of a controllingroller acting by surface contact With' the tympan to control its shifting movement, a governing-disk limiting the rotative movement of said roiier and consequent eXtent of tympan shifted, and a stop-lever limiting the rotative movement of the governing-disk, substantially as described.

27. The combination With an impressioncyiinder and delivering and receiving rollers journaied Within the same for stretching a tympan from one to the other and intermediately over the impression-snrface of said Cylinder, and means for causing the shifting movement of the tympan, of a controllingroller actin g by surface contact with the tympan to control its shifting movement, a governing-disk limiting the rotative movement of said roiler and consequent extent of tympan shfted, a stop-lever limiting the rotative movement of the governing-disk, and a device for tripping said lever, subst-antially as described.

28. The combination With an impressioncylinder and delivering and receiving rollers journaled Within the same fo1` stretching a tympan from one to the other and intermediately over the impression-snrface of said cylinder, and means for cansing the shifting movement of the tympan, of a controllingroiler acting by surface contact With the tympan to control its shifting movement, a governing-disk limiting the rotative movement of said roller and consequent extent of tympan shifted, gearing intermediate the said roller and governing-disk connecting the two and a stop-lever limiting the rotative movement of the disk, substantially as described.

29. The combination With an impressioncylinder and delivering and receiving rollers journaled Within the same for stretchng a tympan from one to'the other and intermediately over the impression-surface of said cylinder, and means for causingl the shifting movement of the tympan, of a controllingro11er acting by surface contact With the tympan to control its shifting movement, a governing-disk limiting the rotative movement of said roller and consequent extent of tympan shifted, gearing intermediate the said roller and governin g-disk connecting the two, a stop-iever limiting the rotative movement of the disk, and a device for tripping said 1ever, snbstantially as described.

30. The combination With an impressioncylinder and delivering and receivng rollers jonrnaled within the same for stretching a tympan from one to the other and intermediately over the impresson-surface of said cylinder, of a Spring -actuated driving-shaft geared With the receiving-roller to rotate it, mechanisms connected With said shaft and operated by the rotation of the cylinder to Wind up the Spring, means for su spending the rotative movement of the tympan-rollers and a tripping device acting to release said rollers and permit their rotation by the action of the Spring to shift the tympan, substantialiy as described.

In testimony Whereof I have hereunto set my hand in the presence of two subscribing witnesses.

LUTHER C. CROVVELL.

`Witnessesz J. J. KENNEDY, A. L. KENT. 

